Arrowhead projectiles of small dimensions and large mass, which are fired from smooth-tube guns at a high initial velocity, achieve a high penetrating power which is advantageous especially in combat against armoured vehicles. So that, in spite of the small projectile cross-section, the predetermined weapon capacity in terms of interior ballistics can be converted into the kinetic energy of the projectiles, sabot projectile guides are used, and these guide the projectile centered during the interior ballistic phase and detach themselves from the projectile after it has left the tube. Their function is comparable to that of a piston. Known sabot projectile guides consist of light metal and/or plastic.
It has been found that sabot projectile guides of this type give rise to unexpectedly high wear in smooth-tube gun barrels. Also, the projectiles are scattered to a considerably greater extent than could have been expected in view of their good design, tolerance calculation and tube length. Typical cold-weld marks caused by light-metal parts, and vein-like flat furrows were observed on the inside wall of the tube, and these impair the firing accuracy especially when they are located in the last portion before the muzzle.
To minimise tilting movements of the projectile guide, which could be responsible for this damage, attempts were made to provide it with guide faces located axially as far apart as possible from one another. This results in a form of the sabot projectile guide with a rear sabot, the periphery of which is intended to rest in a leak-proof manner against the smooth gun barrel, and with a front guide collar interacting with the barrel in a guiding manner. Located between the sabot and the guide collar is an encircling cavity which is enclosed essentially in a leak-proof manner between these two parts and the barrel. The guide collar is recessed toward the front in the form of a bell; as a result, one the one hand, the peripheral face of this collar interacting with the barrel in a guiding manner is to be shifted as far forward as possible, and, on the other hand, it will become easier in aerodymanic terms to remove the multi-part projectile guide from the projectile after it has left the tube.
However, the invention has recognised that this design also has the disadvantage that the pressure, arising during firing, of the air column compressed in the barrel in front of the projectile expands the bellshaped guide collar and presses it against the barrel, and this can result in three-dimensional deformation, bending or vibrations. In severe cases, the application of pressure leads to cold-weld marks in the tube and consequently also to premature tube wear as a result of partial paring-out.